I was out this afternoon just driving the Formula to make sure I worked the bugs out before the tuning session and got caught on the highway in rush hour traffic. For an hour straight ideling at 10 MPH in 96* heat. Bumper to bumper. 0 Issues or fluction in temps. Stayed about 185-190 driving on highway and 195-200 in traffic. Stock thermo and cooling system. Using Dexcool. I figure if it passes this test, cooling is not an issue!